Portable teaching aid



FIG. 1 is a front perspective view of a portable teaching aid showing my new design in operating open or expanded position;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a view in elevation of the opposite side of FIG. 1; and

FIG. 5 is a perspective view of the teaching aid in closed position. 

The ornamental design for a portable teaching aid, substantially as shown. 